innodb_stats_sample_pages
Analysis: If you set the number of analyzed pages
to very low number compared to actual pages on
that table/index it randomly pics those pages
(default 8 pages), this leads to fact that query
after analyze table returns different results. If
the index tree is small, smaller than 10 *
n_sample_pages + total_external_size, then the
estimate is ok. For bigger index trees it is
common that we do not see any borders between
key values in the few pages we pick. But still
there may be n_sample_pages different key values,
or even more. And it just tries to
approximate to n_sample_pages (8).
Fix: (1) Introduced new dynamic configuration variable
innodb_stats_sample_traditional that retains
the current design. Default false.
(2) If traditional sample is not used we use
n_sample_pages = max(min(srv_stats_sample_pages,
index->stat_index_size),
log2(index->stat_index_size)*
srv_stats_sample_pages);
(3) Introduced new dynamic configuration variable
stat_modified_counter (default = 0) if set
sets lower bound for row updates when statistics is re-estimated.
If user has provided upper bound for how many rows needs to be updated
before we calculate new statistics we use minimum of provided value
and 1/16 of table every 16th round. If no upper bound is provided
(srv_stats_modified_counter = 0, default) then calculate new statistics
if 1 / 16 of table has been modified
since the last time a statistics batch was run.
We calculate statistics at most every 16th round, since we may have
a counter table which is very small and updated very often.
@param t table
@return true if the table has changed too much and stats need to be
recalculated
*/
#define DICT_TABLE_CHANGED_TOO_MUCH(t) \
((ib_int64_t) (t)->stat_modified_counter > (srv_stats_modified_counter ? \
ut_min(srv_stats_modified_counter, (16 + (t)->stat_n_rows / 16)) : \
16 + (t)->stat_n_rows / 16))
The bug was that full memory barrier was missing in the code that ensures that
a waiter on an InnoDB mutex will not go to sleep unless it is guaranteed to be
woken up again by another thread currently holding the mutex. This made
possible a race where a thread could get stuck waiting for a mutex that is in
fact no longer locked. If that thread was also holding other critical locks,
this could stall the entire server. There is an error monitor thread than can
break the stall, it runs about once per second. But if the error monitor
thread itself got stuck or was not running, then the entire server could hang
infinitely.
This was introduced on i386/amd64 platforms in 5.5.40 and 10.0.13 by an
incorrect patch that tried to fix the similar problem for PowerPC.
This commit reverts the incorrect PowerPC patch, and instead implements a fix
for PowerPC that does not change i386/amd64 behaviour, making PowerPC work
similarly to i386/amd64.
* use the same HAVE_C/CXX_ variables for compiler flag tests as the rest of
the server and tokudb - to use cached results
* plugin's name should be "mroonga" not "ha_mroonga"
* don't use set_property(TARGET plugin_name ...), it aborts cmake when a plugin
id disabled, because the target doesn't exists in that case
result: mroonga can now be disabled from cmake command line
ALTER TABLE: don't fill default values per row, do it once.
And do it in two places - for copy_data_between_tables() and for online ALTER.
Also, run function_defaults test both for MyISAM and for InnoDB.
They are still experimental and should not be used in production.
added:
storage/connect/encas.h
storage/connect/english.msg
storage/connect/enids.h
storage/connect/frcas.h
storage/connect/french.msg
storage/connect/frids.h
storage/connect/frmsg.h
modified:
storage/connect/connect.cc
storage/connect/engmsg.h
storage/connect/filamdbf.cpp
storage/connect/global.h
storage/connect/ha_connect.cc
storage/connect/msgid.h
storage/connect/plgdbutl.cpp
storage/connect/plugutil.c
storage/connect/rcmsg.c
storage/connect/resource.h
storage/connect/tabfmt.h
- Fix global variable not being properly initialized (MDEV-6690, MDEV-7094)
modified:
storage/connect/ha_connect.cc
storage/connect/plugutil.c
storage/connect/user_connect.cc
storage/connect/xindex.cpp
- Implement Rewind for ODBC tables (MDEV-7097)
modified:
storage/connect/odbconn.cpp
storage/connect/odbconn.h
storage/connect/tabmysql.cpp
storage/connect/tabodbc.cpp
- Reset N when reopening MYSQL tables
modified:
storage/connect/tabmysql.cpp
buildbot on work-amd64-valgrind
Fixed issue by finding out first the current used priority
for both treads and using that seeing did we really change
the priority or not.
setting of innodb_io_capacity_max
(a) Changed the behaviour so that if you set innodb_io_capacity to a
value > innodb_io_capacity_max that the value is accepted AND
that innodb_io_capacity_max = innodb_io_capacity * 2.
(b) If someone wants to reduce innodb_io_capacity_max and
reduce it below innodb_io_capacity then innodb_io_capacity
should be reduced to the same level as innodb_io_capacity_max.
In both cases give a warning to user.
Analysis: InnoDB error monitor is responsible to call every second
sync_arr_wake_threads_if_sema_free() to wake up possible hanging
threads if they are missed in mutex_signal_object. This is not
possible if error monitor itself is on mutex/semaphore wait. We
should avoid all unnecessary mutex/semaphore waits on error monitor.
Currently error monitor calls function buf_flush_stat_update()
that calls log_get_lsn() function and there we will try to get
log_sys mutex. Better, solution for error monitor is that in
buf_flush_stat_update() we will try to get lsn with
mutex_enter_nowait() and if we did not get mutex do not update
the stats.
Fix: Use log_get_lsn_nowait() function on buf_flush_stat_update()
function. If returned lsn is 0, we do not update flush stats.
log_get_lsn_nowait() will use mutex_enter_nowait() and if
we get mutex we return a correct lsn if not we return 0.
on work-amd64-valgrind.
Fixed issue by finding out first the current used priority
for both treads and using that seeing did we really change
the priority or not.
COMMUNICATION PACKETS; FEDERATED TABLE
Description:- Execution of FLUSH TABLES on a federated
table which has been idle for wait_timeout (on the remote
server) + tcp_keepalive_time, fails with an error,
"ERROR 1160 (08S01): Got an error writing communication
packets."
Analysis:- During FLUSH TABLE execution the federated
table is closed which will inturn close the federated
connection. While closing the connection, federated server
tries to communincate with the remote server. Since the
connection was idle for wait_timeout(on the remote server)+
tcp_keepalive_time, the socket gets closed. So this
communication fails because of broken pipe and the error is
thrown. But federated connections are expected to reconnect
silently. And also it cannot reconnect because the
"auto_reconnect" variable is set to 0 in "mysql_close()".
Fix:- Before closing the federated connection, in
"ha_federated_close()", a check is added which will verify
wheather the connection is alive or not. If the connection
is not alive, then "mysql->net.error" is set to 2 which
will indicate that the connetion is broken. Also the
setting of "auto_reconnect" variable to 0 is delayed and is
done after "COM_QUIT" command.
NOTE:- For reproducing this issue, "tcp_keepalive_time" has
to be set to a smaller value. This value is set in the
"/proc/sys/net/ipv4/tcp_keepalive_time" file in Unix
systems. So we need root permission for changing it, which
can't be done through mtr test. So submitting the patch
without mtr test.
default ending. Also takes care of files having mixed line endings.
This is done by never using text mode for streams and handle the line
endings in reading and writing. (MDEV-7030)
modified:
storage/connect/filamtxt.cpp
Analysis: InnoDB error monitor is responsible to call every second
sync_arr_wake_threads_if_sema_free() to wake up possible hanging
threads if they are missed in mutex_signal_object. This is not
possible if error monitor itself is on mutex/semaphore wait. We
should avoid all unnecessary mutex/semaphore waits on error monitor.
Currently error monitor calls function buf_flush_stat_update()
that calls log_get_lsn() function and there we will try to get
log_sys mutex. Better, solution for error monitor is that in
buf_flush_stat_update() we will try to get lsn with
mutex_enter_nowait() and if we did not get mutex do not update
the stats.
Fix: Use log_get_lsn_nowait() function on buf_flush_stat_update()
function. If returned lsn is 0, we do not update flush stats.
log_get_lsn_nowait() will use mutex_enter_nowait() and if
we get mutex we return a correct lsn if not we return 0.
modified:
storage/connect/filamap.cpp
- ftell error: indicate in the error msg that is can be due to wrong ENDING value.
filamtxt.cpp (MDEV-7030)
modified:
storage/connect/filamtxt.cpp
- Change STRING according to Alexander Barkov remarks.
Suppress the wrong Strz function. The unconditional function strz is no more
used for s->db and s->table_name because they are zero terminated.
modified:
storage/connect/ha_connect.cc
storage/connect/xobject.cpp
- Change version number
modified:
storage/connect/filamap.cpp
- Change PATH_MAX to FN_REFLEN (MDEV-7036)
modified:
storage/connect/os.h
storage/connect/tabmul.cpp
- Fix bug by adding a void argument for OP_NOT in Makefilter.
modified:
storage/connect/filter.cpp
- Begin implementing XMSG style
Two new system variables are defined:
msg_lang ENUM session
errmsg_dir_path STR global readonly
This is a work in progress.
modified:
storage/connect/ha_connect.cc
storage/connect/plgdbutl.cpp
storage/connect/plugutil.c
storage/connect/rcmsg.c
storage/connect/resource.h
Description:
Using correct length when moving to next field in cmp_ref. The store
length already includes the length bytes of blobs, which is already considered
earlier for blob types.
Approved by Mattias, Jimmy [rb-7088]
